Process of making casein



y 1935. D. N. BURRUSS, JR., ET AL 2,007,962

PROCESS OF MAKING CASEIN Filed March 17, 1933 2 Sheets-Sheet 1 DavzdMburrwsJr'. John 1? Ruth CLMMW iii-Ml July 16 1935. N. U J ET AL2,007,962

PROCESS OF MAKING CASEIN Filed March 17, 1933 2 Sheets-Sheet 2 Air:Inlet;-

Damd MBurrussJn John P. Ruth.

Patented July 16, 1935 PROCESS OF MAKING CASEIN David N. Burruss, In,St. Louis, Mo., and John P. Ruth, Collinsville,'lll., assignors toChemical and Pigment 00., Inc., Collinsville, 111., a corporation ofMaryland Application March 1'7, 1933, Serial No. 661,407

3 Claims.

This invention relates to the manufacture of casein-from vegetablematter and has particular reference to the production of casein fromsoya bean meal by a new and highly efficient process.

In the manufacture of casein from vegetable matter, such as soyabeanmeal, it is customary to operate with dilute dispersions of the meal inwater, the concentration-of the meal in water varying from one part ofmeal to parts by 10 weight of water to one part of meal and parts ofwater. To these dilutions of meal and water are added various extractingagents. Since casein derived from either vegetable matter or milk isamphoteric, these extracting agents may be either acid or alkaline incharacter. The extreme dilutions involved in the processes heretoforeemployed for obtaining a suitable casein require proportionally largeramounts of the extracting agents than wouldbe necessary if higherconcentrations were used.

After the protein or casein has been converted to the soluble form inthe processes heretofore used, the extraneous matter, such as cellulose,albumin, etc., is removed by either filtration or settling. The fairlyclear liquid-resulting from the filtration containing the soluble caseinor protein is then reprecipitated by either acid or alkali, depending onwhether an alkali or an acid was used for dissolving and extraction. Ifan alkali was used for extraction, the usual precipitant is eitheracetic, sulphuric or muriatic acid, although other acids may be usedwith varying results. If an acid is used for the extraction of theprotein, an alkali such as ammonium hydroxide or soda ash is used forthe precipitation. In either method, a very finely-divided, gelatinous,slimy, colloidal precipitate results which is very diificult to filterand is very sensitive to external conditions, such as temperature,bacterial fermentation, etc. As a consequence of these objectionableconditions involved in filtering and handling the precipitated casein,therefhas been great difficulty in producing a uniformly, high iii ablein cost and quality to the higher grade milk grade casein commerciallythat would be comparbarium, etc., have been known for a long time, notonly has no economic process to date been evolved for commercialmanufacture of these products but the equipment employed has also beeninadequate and unsatisfactory for handling 5 these products so as to drythem to a suificient degree to render them stable to atmosphericconsimplified, easier of operation, of greater eficiency 20 andextremely more economical as to cost and reagents and materials used.

Other, further and more specific objects of this invention will becomereadily apparent to persons skilled in the art from a consideration ofthe 25 following description when taken in conjunction with theaccompanying drawings wherein:

Fig. 1 shows more or less diagrammatically a battery of extraction tanksoperating on the counter-current principle in combination with a 30dryer used in our process for handling the washed but undried casein.

Fig. 2 is an enlarged fragmental detail View, partly in section, showinga suitable form of nozzle employed in the dryer.

Fig. 3 is a top plan view of one of the series oi. tanks shown in Fig.1, employing a rake near the bottom for moving settled material.

Fig. 4 is a vertical section through one of the tanks having a rake nearthe bottom. 40

The apparatus for carrying out the novel process of this inventioncomprisesa precipitating tank A and a plurality of tanks B, C, D and E,operating in series and forming a battery for conducting the process onthe counter-current 45 principle. Tank A is provided with a stirrer oragitator l for keeping material in suspension and thoroughouly agitated.The tanks B, C, D and E are preferably provided with downwardlysloplug"conical bottoms 2 which accommodate the 50 rakes 3 positioned near thebottom of each tank, serving to agitate and remove settled material.Water is introduced through the pipe 4 into tank E and the overflow fromthis tank passes through the pipe 5 into the top of tank l'). Tn

like manner, the overflow from tank D is brought to the top of tankthrough the pipe 6 and the overflow from tank C is brought into the topof tank B through the pipe I. If desired, the overflow from one tank maybe pumped to the succeeding tank instead of depending upongravity Sodiumcaseinate, in dry form or solution and prepared by any suitable manner,is introduced at 8 at the top of the tank A and the precipitating acidis also introduced at some suitable point 9 at the top of this tank. Theacid, such as muriatic, sulphuric, acetic, etc. is preferably dilutedand of such strength as will not break down the protein molecule. Wenormally employ a dilution of 1 part to 10 parts of water, but this canbe further diluted to 20 parts of water for 1- part of acid. Sufficientwater should be provided in tank A for dissolving the sodium caseinateif introduced in dry form. After the casein has been precipitated intank A, the entire contents are transferred through the pipe Hi to thetank B. The casein is withdrawn from the bottom of this tank B throughthe pipe 'H in the form of a sludge and pumped into the top of tank Cwhere the casein is again washed, and from this tank C the casein isagain withdrawn at the bottom through the pipe I2 and pumped to the topof the tank D where a further washing takes place. The casein is in likemanner withdrawn as a sludge from the bottom of tank D through the pipeI3 and pumped into the top of tank E.

After the final washing in tank E the casein in the form of a sludge iseitherdelivered directly into the spray dryer or else passed into asupply tank F from which it is withdrawn as desired through the pipe l4and forced by the positive flow pump l5 through the central passage IGof the nozzle, I! while air under suitable pressure (from 5 to 70 poundsper square inch) is forced through the surrounding jacket l8. Theaqueous dispersion of casein is thus sprayed into the hotair which isblown through the pipe I9 by means of the fan 20 surrounded by theheater 2|. The casein is immediately dried and carried into the settlingtank 22 where the dry casein falls to the bottom and is withdrawn bymanipulation by the gate 23, while air which has become wet byabstracting water from the casein passes out through the top 24.

Precipitated casein is of a slimy, colloidal nature of extremely fineparticle size that does not readily lend itself to any of the commonforms of filtration. This difliculty of de-watering precipitated caseinhas been well recognized by those skilled in the art. In order to removethe water from the precipitate it has been necessary to resort either tothe use of centrifugespr curd presses. Either of these methods arecostly and inefficient owing to the time and labor involved and thelosses sustained. Our process dispenses with filtration and eliminatesthe objections incident to the present method of filtration which avoidsthe losses sustained by these methods.

In the prior process employing simple tunnel or atmospheric dryers,after subjecting the precipitated casein to any of these unsatisfactoryfiltration processes, the material was expmed to a current of warm airfor a long period of time for breaking up the dried product. That partof the material which has been oxidized and has become horny remains inthe ground finished" filtration, for'example, by the use of anhydrouswater soluble solvents, the process is not only expensive but in mostcases injurious to the finished product, due to the formation ofaddition product compounds with the casein.

All of these objectionable features incident to the filtrationand dryingin the prior processes are eliminated in our process, as we employ nocostly or injurious, anhydrous, water soluble solvents for eliminatingthe water and we prevent oxidation and formation of horny masses byinstantly drying the casein in a saturated atmosphere. With our processno grinding of the dried material is necessary, as the product is driedin a very finely divided form and the finished casein isfiner than mostcasein produced by any of the other processes, all of which require thegrinding of the dried material. Our casein is of uniform size andtexture and is readily soluble in any -of the common solvents forcasein. The low uct. Our process has so simplified operation as 1 tomake soya' bean casein commercially available.

The sodium caseinate employed for this process is obtained by treatingsoya bean meal with an aqueous solution of an alkaline sodium salt orsodium hydroxide. Sodium sulphite has been found very satisfactory andyields 'a caseinate of little or negligible coloration. The corre--spending compounds of potassium, ammonium I and magnesium may beemployed in lieu of the sodium compounds- We prefer to employ soya beanmeal from which the greater part of the natural oily constituents havebeen removed. Ourpr'ocess, however, is applicable to soya bean meal' andother casein-containing vegetable matter from which little' or none ofthe oil has been extracted as well as other casein-containing vegetablematter from which the greater part of the natural oily constituents havebeen removed.

During the washing of the casein by the counter-current method, thismaterial is passed from tank B to tank C, tank C to tank D and tank D totank E, and as the overflow from tank E passes to tank D, the overflowfrom tank D to tank C and the overflow from tank C to tank B, the liquidin tank B contains the dissolved sugars, albumins and other proteidswhich are not precipitated by the acid. The overflow from tank Bcontaining these materials may be passed into a supply tank G from whichit is withdrawn as desired through the pipe 25 and forced by thepositive flow pump 26 into the central passage ii of the nozzle I! whileair under suitable pressure (5 to 70 pounds per square inch) is forcedthrough the surrounding jacket l8. The solution 'containing thedissolved sugars, albumins, etc.,

is thus sprayed into the hot air which is blown through the pipe l9 bymeans of the fan 20 surrounded by the heater 2|. The solid portion isimmediately dried and carried into the settling chamber where it fallsto the bottom and is withdrawn'by manipulation of the gate 23 while theair which has become wet by abstracting water from the solution passesout through the top 24. The sugars, albumins and proteids are recoveredin dried form for such uses as may be desired.

In the spray drying process which we employ, less air is required forspraying the solution containing the dissolved sugars, albumins, etc.than is required for the aqueous suspension of the casein. Due to thequantity of water contained in the solution, the rate of feed to thedryer is slower than when the suspensions are treated. This method ofdrying removes the water from the sugars, albumins, and other proteidswithout injuriously affecting the same. If it is desired to produce acasein of a very high degree of purity, the washed casein from tank Emay be redissolved by an alkaline reagent and then reprecipitated by-anacid. The latter precipitate is then passed through the series of tanksand subjected to counter-current washing, after which it is dried in thespray dryer. .In the drying operation, the air is heated to between 100C. to 140 C. The temperature after the air has passed the nozzle of thespray may vary from 30 C. to 100 C. This temperature is governed by thepercentage of moisture desired in the finished product and by thetemperature to which the finished product may be heated without injury.Normally, the temperature of the air after passing the nozzle of thespray is from 55 C. to 70 C.

It will be seen by reference to Fig. 2 that the central passage N5 ofthe nozzle is of the same size and shape throughout its entire lengthand is therefore non-choking. We also dispense with the use of a jet orother nozzle at the spray end. The jacket I8 is threaded in the holder21 and is adjustably movable therein by merely gripping this jacket l8at 28 and turning. This permits regulation of the distance between thetop of the central passage l6 and the top of the jacket I8, therebyproviding a convenient means for regulating the spray. This regulationof the spray affords a very effective and highly desirable means forvarying the physical characteristics of the dry product.

The present invention is not limited to the specific details set forthin the foregoing examples which should be construed as illustrative andnot by way of limitation, and in view of the numerous modificationswhich may be afiected therein without departing from the spirit andscope of this invention, it is desired that only such limitations beimposed as are indicated in the appended claims.

We claim as our invention 1. A process comprising precipitating caseinin a slimy, colloidal nature of extremely fine particle size from anaqueous solution containing dissolved vegetable caseinate obtained fromsoya beans, subjecting this colloidal precipitated casein to a series ofaqueous treatments wherein the undissolved portion after each treatmentis subjected to the next treatment while aqueous liquid is passed fromeach treatment to the next treatment in a direction counter to thepassage of said undissolved portion, and then spraying into a stream ofhot air the aqueous sludge of casein resulting from the aqueoustreatments.

2. A process comprising extracting soya bean meal with an aqueousalkaline solution, treating the resulting extract with an acid andprecipitat ing casein therefrom in a slimy, colloidal nature ofextremely fine particle size, subjecting this colloidal precipitatedcasein to a series of aqueous treatments wherein the undissolved portionafter each treatment is subjected to the next treatment while aqueousliquid is passed from each treatment to the next treatment in adirection counter to the passage of said undissolved portion, and thenspraying into a stream of hot air the aqueous sludge of casein resultingfrom the aqueous treatments.

3. A process comprising precipitating casein in a slimy, colloidalnature of extremely fine particle size from an aqueous solutioncontaining dissolved vegetable caseinate obtained from soya beans,subjecting this colloidal precipitated casein to a series of aqueoustreatments wherein the undissolved portion after each treatment issubjected to the next treatment while aqueous liquid is passed from eachtreatment to the next treatment in a direction counter to the passage ofsaid undissolved portion, and then spraying into a stream of hot air amixture of air and the aqueous sludge of casein resulting from theaqueous treatments.

DAVID N. BURRUSS, J 11. JOHN P. RUTH.

